MOBILE-3320 core: Prevent new line to be shown before submit

src/core/components/send-message-form/core-send-message-form.html

@@ -1,7 +1,21 @@
 <form #messageForm>
-    <textarea class="core-send-message-input" [core-auto-focus]="showKeyboard" [placeholder]="placeholder" rows="1" core-auto-rows
+    <textarea
-        [(ngModel)]="message" name="message" (onResize)="textareaResized()" (keyup.enter)="enterClicked($event)"
+        class="core-send-message-input"
-        (keyup.control.enter)="enterClicked($event, 'control')" (keyup.meta.enter)="enterClicked($event, 'meta')"></textarea>
+        [core-auto-focus]="showKeyboard"
+        [placeholder]="placeholder"
+        rows="1"
+        core-auto-rows
+        [(ngModel)]="message"
+        name="message"
+        (onResize)="textareaResized()"
+        (keyup.enter)="enterKeyUp($event)"
+        (keyup.control.enter)="enterKeyUp($event, 'control')"
+        (keyup.meta.enter)="enterKeyUp($event, 'meta')"
+        (keydown.enter)="enterKeyDown($event)"
+        (keydown.control.enter)="enterKeyDown($event, 'control')"
+        (keydown.meta.enter)="enterKeyDown($event, 'meta')"
+    >
+    </textarea>
     <ion-button fill="clear" size="large" type="submit" [disabled]="!message || sendDisabled"
         [attr.aria-label]="'core.send' | translate" [core-suppress-events] (click)="submitForm($event)">
         <ion-icon name="send" color="dark" slot="icon-only" aria-hidden="true"></ion-icon>

src/core/components/send-message-form/send-message-form.ts

@@ -103,13 +103,34 @@ export class CoreSendMessageFormComponent implements OnInit {
         this.onResize.emit();
     }
 
+    /**
+     * A11y key functionality that prevents keyDown events.
+     *
+     * @param e Event.
+     */
+    enterKeyDown(e: KeyboardEvent, other?: string): void {
+        if (this.sendDisabled) {
+            return;
+        }
+
+        if (this.sendOnEnter && !other) {
+            // Enter clicked, send the message.
+            e.preventDefault();
+            e.stopPropagation();
+        } else if (!this.sendOnEnter && !CoreApp.isMobile() && other == 'control') {
+            // Cmd+Enter or Ctrl+Enter, send message.
+            e.preventDefault();
+            e.stopPropagation();
+        }
+    }
+
     /**
      * Enter key clicked.
      *
      * @param e Event.
      * @param other The name of the other key that was clicked, undefined if no other key.
      */
-    enterClicked(e: Event, other?: string): void {
+    enterKeyUp(e: Event, other?: string): void {
         if (this.sendDisabled) {
             return;
         }